Grinding mill



W. M. HILL GRINDING MILL Sepi. 6, 1932.

Filed Aug. 28, 1928 3 Sheets-Sheet l INVENTOR. W M. H/LL- TTORNEY. I

Sept. 6, 1932. w. M. HILL 1,876,416

GRINDING MILL Filed Aug. 28. 1928 3 Sheets-Sheet 2 INVENTOR. W. M. H I 1- L ATTORNEY.

Sept. 6, 1932. w. M. HILLIL 1,876,416

GRINDING MIT/715 Filed Aug. 28/ 192 s 5 sheet s-sheet 3 g v T "EL/277i INVENTOR.

Y a 4 j A TORNEY.

Patented Sept. 6, 1932 "are STATES PATENi'Iif OFFICE WALTER iu. HILL, or Henson, coLoReno, AS'SIGNOR, .BY ninnc'r AND mnsnr. Assien-j MENTS, TO J. n. CANARY, or LITTLETON, COLORADO I v GRINDING MILL Application filed. August 28, 1,928.

if i This invention relates to' grinding mills and more particularly to mills of the type in whichmaterial fed onto a rotary impact element is thrown outwardly by centrifugal force against a relatively stationary impact wall and is thereby reduced in size. It is an object of in a mill of the above described character, impact-members on the rotary element, which cause the material to be, batted back and forth between the rotary and stationary elements,'until it is completely and uniformly reduced to the required fineness.

A further object of the present invention is to provide in a mill in which a plurality of pulverizing units are disposed one above another to reduce material fed onto the upper unit in successive steps, a novel means for feeding material to the mill. I It isthe aim of the improved feeding means to increase the capacity ofthe mill, to reduce wear, to assist inthe production of a product of uniform size, and to eliminate the use of hoppers that are'objectionable for many reasons and particularly because of'their tendency to feed the material onto the rotary impact element in an arbitrary and uneven manner.

Another object resides in the provision of impact-members of novel construction, and of novel means for mounting the members upon the disks that constitute the rotary elements, and still further objects reside in details of construction as will be brought out in the course of the following description.

' In the accompanying drawlngs in the several views of which like parts are similarly designated;

Figure 1 represents a vertical section through a mill of the improved construction, Figure 2, an enlarged fragmentary section through one of the pulverizing units, as on the line 2 2, Figure 1, Figure 3, a section along the line 3-3, Figure 2, Q

Figure 1, a horizontal section taken on the line 4% 1, Figure 1,

Figure .5, a fragmentary plan view of one of the disks, showlng a modified construction of the imp act-members,

the invention to provide form, and its horizontal tion.

Serial No. 302,523. m Figure 6, a section along thefline 6-6, Figure5, i I

Figure 7, a view similar to Figure 5, showing another modification of the impact? member,

Figures 8,

plane of Figure the construction of the in the invention,

Figure 11, a horizontal sectionon the line 11-11,Figure 8, i Figure 12, a si 1212, Figure 9, and I V Figure 13, a horizontal section showing another modification of the distributing member. f The mill as shown comprisesa plurality of pulverizing units ofp'rogressively increasing diameters, superposed one above another from the top of the mill at which the mate-- rial' is fed, to the bottom of the mill at which the product of the successive pulverizing ac-J tions is discharged. Each unit comprises a circular part of a shell 5 to which is fastened a correspondingly formed impact or breakerring 6', a disk 7 mounted to rotate'about an axis coincident with that of the ring, and having i'ts periphery spaced from the ring,

1, showing modifications in feed-element included and a 'SGI'lQS of blades 8 fastened at the periphery of the disk. v

. The shell 5 provides a housing of stepped surfaces at the top of each unit, are protected by lining plates 9. It is preferred to construct this housing in sections which areconnected-by bolts '10 in registering apertures of outwardly projecting flanges 12.

Beneath the housing is a discharge hopper 13 having a central opening 14 and provided with an outwardly projecting flange 15 for its support upon a suitable foundation The box 16 of a step-bearing in the vertical axis of the discharge hopper,is formed intogral therewith by radial webs 17 and the box contains a roller bearing S and a series of washers 19 for the support of a vertical shaft 20 upon which the disks of the several pulverizing units are mounted for conjoint rota- Another bearing 21for the shaft,-simi-. larly constructed, is supported by legs 22 9 and 10, sectional views in the milar section on the line 7 The boX of the lower bearing is closed by a {5 cap 24 and a lubricant may be supplied to the 1 key 27, and they are by collars 28. A nut bearing while, the mill is in operation, through pipes 25 and 26.

The disks 7 are fastened on the shaft by a spaced from each other 29 screwed upon a screw threaded portion of the shaft, reduced in diameter, serves to hold the disks against vertical displacement. I w W a Immediately above the upper grinding unit is a feed-chamber 30, the circular wall 31 of which may "consist of a smooth lining of White iron fastened inside the corresponding upright part of the housing. The feed-chamer is smaller in diameter than the upper grinding chamber in substantially the same ratio at which each grinding unit is larger than the one immediately above the same.

The wear ring 31 is not an essential and may be eliminated, or under certain conditions it may be corrugated as indicated in Figure 12.

Inside the feed chamber is a feed disk 32 which is spaced from the wall thereof and is supported upon the disk of the upper grinding unit by a collar 33. The feed disk is fastened on the shaft by the same key that holds the disks of the pulverizing units, and the aforementioned nut engages upon a washer 34 supported on the feed disk.

The top-plate 23 of the mill has one or more openings 35 through which material is fed into the feed chamber, and spouts 36 may be provided to direct the feed to the openings.

The feed disk functions to distribute the material supplied through one or more openings at the top of the housing, evenly and uniformly upon the disk of the upper pulverlz ng unit. The feed is e'flected by centrifugal force and overloading of any part of the disks of the pulverizing units as frequently occurs in the use of stationary hoppers, is entirely avoided. The rotating feed disk distributes the material evenly and entirely around the mill at all times during its operation. The capacity of the mill is thereby increased and a product of constantly uniform fineness is assured.

The feed plate may be fiat as shown in Figure 1 of the drawings, or it may be provided with retarding means such as the concentric rings indicated at 46 in Figures 9 and 12, or radiating curved ribs shown at 4-7 in Figure 13.

The disk may also be provided with acircumferential flange or rim shown at 48 in Figures 8 and 11, in which case it will fill with material having its surface slope inwardly to the axis of rotation. The material distributed by the rotary motion of the disk,

caving the feed diskto will thus move across a bed of fine material held by the flange, which eliminates Wear and promotes attrition. The material slidlng toward the circumference of the feed disk at an upward angle, will be retarded and therefore be more evenly distributed.

In this connection, it will be understood that a similar result may be obtained by conas illustrated at 49 inFig-ure 10, it being evident that any means for retarding the movement of the material across the feed disk will aid in effecting a better and more even distribution of the material around the mill.

The disks of the pulverizing units are each equipped with a plurality of blades that are. preferably equidistantly, arranged at the peripheriesof the disks. The blades extend radially of the disks and their outer ends which are in line with the peripheries of the respective disks, are toothed or corrugated as shown at 37. The drawings show three blades of different constructions and it is to be understood that other modifications may be made within the scope of the invention. The blade shown in Figure 2 is of sector-form and is secured to the disk by a countersunk machine bolt 38.

In order to hold the blade against sidewise movement, it has at its lower surface, a non-circular tenon 39 that fits in a correspondingly shaped mortise 40 in the upper surface of the disk. I The form of blade illustrated in Figure 7 differs from the only in that the tenon is omitted and in that two bolts are provided to rigidly secure the hammer in place on the disk. The blade 41 illustrated in Figures 5 and 6,

the shape of a saucer one hereinabove described,

is toothed at opposite ends and it is fastened to the disk by means of a central bolt 42. When one end of the blade is worn, the blade may be turned about the bolt to bring the other toothed face in line with the periphery of the disk. It has been found in practice that the blades Wear quickest at the forward end of their toothed faces with relation to the direction of rotation of the disk, and this being the case, the usefulnessof the blade may further be prolonged by turning it upside down on the disk so that the opposite end of its working face is exposed to the abrasive action of the material under treatment. It

will thus be observed that the blade can be addifferent positons before its The blade shown in Figure 5 is rigidly held 1310 breaker ring.

in its operative position by a lock consisting of block 43 fastened on the disk by a bolt 44 and having teeth that interlock with those at the inner end of the blade.

It is desirable that the number of blades on each disk is in ratio to the diameter thereof so that each larger disk carries more hammers than the smaller disk or disks above the same.

In the operation of the machine the material fed through the openings of the top plate falls on the feed disk 32 in the feed chamber 30 and is thereby uniformly distributed about the periphery thereof, as hereinbefore explained.

It is to be observed that each disk is propor-' tioned so that its periphery falls within the vertical planes of the inner ends of the impact-members of by causing the material that passes downs wardly through the annular passage of the feed chamber or t irough of each upper pulverizing unit to fall upon the next lower disk in the zone Within the series of peripheral blades thereof.

The material fed upon the disk of each pulverizing unit moves outwardly by centrifugal force within the path of the blades which throw it violently against the toothed The impact of the materia with the teeth of the ring causes it to reboun against the teeth ofthe blades on the disk and the material is in this manner batted back and forth until it is reduced to a size that permits of its being drawn downwardly by the suction produced in the operation of the mill, through the annular passage of the unit between the disk and the breaker ring, into the next lower unit where the operation is repeated.

The material thus subjected to a succession of pulverizing actions is gradually reduced to the desired fineness and finally discharged from the machine through the hopper 13.

The back and forth movement of the material between the blades and the breaker ring in the pulverizing units has been indicated in Figure 2 by the arrows 45. I

The toothed blades, coacting with the surrounding breaker rings, are adapted to extremely fine grinding and produce a material increase in the capacity of the mill over similar machines employing blades or hammers, the ends of which are smooth.

In mills of the last mentioned type, thematerial after having been thrown against the breaker ring would be discharged without further diminution into the next lower unit in a mixture of fine matter and large unground particles.

In the present mill the toothed blades cause the material to be batted back and forth as indicated by the arrows 45, until it is uniformly reduced to the desired fineness, ow-

the next lower disk there-' the annular passage diameter from the verizing units increasing only reduced by itsuforceful impacts with but also by the attrition of the optheseparts,

streams asthey cross one positely moving another.

The hammers mayhave one or more teeth,

and owingtothefact thatthe materialdoes not pass in a constant stream across the ends of the hammers aswasthe case where smoothended bladeswerensed, the hammers are less sub ect to wear.

Iclaim and desire to secure by Letters Patent is: L In a pulverizing mill, a pulverizing unit compr sing a circular impact wall, a rotary d sk spaced from the wall, blades reversibly mounted on the disk and having impact-ends one of which is at the periphery ofthe same, and means for locking g-said blades against lateral displacement. f 2. Ina pulverizingmill, a pulverizing unit comprising a circular impact wall, a rotary disk spaced from the wall, andblades reversibly mounted on the disk, each blade having opposite toothed ends, one of which 1 is at the periphery of,- the disk. I

3. In a pulverizing mill, a pulverizing unit comprising a circular impact wall, a rotary disk spacedfrom the wall, a blade reversibly. mounted on the disk, the blade having opposite toothed ends, one of which is at the'periphery of the disk, and means for locking the blade in place by engagement with the teeth at the inner end thereof. 1 I a eiflve izinam L a pu reriz ngz nit comprising a circular impact wall, a rotary disk spaced from thewall,a blade reversibly mounted on the disk, the blade having'oppo: site toothed ends, one of which is at, the pee ripheryof thedisk, and a toothed block on the disk meshing with the inner teeth of the bladeto lockthe-blade in place, I p

5. In a pulverizing mill, a plurality of pulverizing units increasing successively in topv of the mill and each including a circular impact wall, a disk spaced from'the wall, and impact-members on the disk at the periphery thereof, the Space of each unit being above the; disk of the next lower unit, means for feeding'material to the upper unit, a shaft on which the disks of the units are mounted for conjoint rotation, a discharge hopper below the lower unit, and a bearing by the hopper. Y

6. In a pulverizing mill, a plurality of pulsuccessively in di-, am'eter from the top of the mill and each including disk spaced from the wall, and impact members on the disk at the periphery thereof,

for the shaft supported a circular impact wall, a rotary in the chamber the space of each unit being above the disk of the next lower unit, means for feeding material to the upper unit, a shaft on which the disks of the units are mounted for conjoint rotation, a discharge hopper below the lower unit, a bearing for the shaft supported by the hopper, and a bearing for the shaft at the top of the mill.

In a pulverizing mill of the character described, a pulverizing unit, a circularfeed chamber above the unit, and a-rotary feed disk having means for retarding the movement by centrifugal action of material to said unit, and being peripherally spaced from the wall of the chamber.

8. In a pulverizing mill, a grinding chamber having a continuous circular wall and a feed-opening, and a rotary feed member below the feed-opening and Spaced from the wall, to impel material to ward the wall by centrifugal force, the feedmember being adapted to oppose the outward movement by centrifugal force, of the material.

9. In a pulverizing mill, a grinding chamber having a continuous circularwall and a feed-opening, and a rotary feed member in the chamber below the feed-opening and spaced from the wall, to impel material to ward the wall by centrifugal force, the feedmember having a material-retaining rim.

10. A pulverizing mill comprising a vertical shaft, horizontal grinding chambers disposed one above another whereby material ftt mg members at the signature. 65

may descend by gravity from one to another, the chambers having toothed circular impact surfaces, horizontal rotary disks on the shaft and disposed in the chambers, and grind peripheries of the disks, having teeth opposed to those of the impact surfaces, the teeth of the upper impact surface being disposed to direct material inside the grinding members on the lower disk.

11. A pulverizing mill, comprising a grinding chamber having a continuous circular wall and a feed opening, and a rotary feed member in the chamber opposite the feed opening and spaced from the wall, to'impel material toward the wall by centrifugal 50 force, the feed member having upturned means to retard material crossing the memher.

In testimony whereof I have affixed my WALTER M. HILL. 

